Grate the peeled potatoes and onions with the grater blade.
Remove the mixture and transfer to a large bowl. Fit the food processor with the S blade. (Alternatively process on speed 8 with the Braun) Transfer the mixture back to the food processor.
Pulse for about 1 minute. Transfer the mixture back to the bowl.
Process the remaining ingredients for 1-2 minutes.
Combine the liquid with the potato mixture in the bowl, and mix well.
Transfer to a pan and bake on 425 F for 1 hour and 30 minutes.
Lower the oven temperature to 200F. Cover the foil pan with a sheet of foil and a foil pan lid.
Bake for 8 hours.
